With rapid development of semiconductor technology, the properties of integrated circuit (IC) have continuously increased. The structure of the integrated circuit becomes more complicated, so the manufacture method of the integrated circuit, more specifically, the packaging method of the integrated circuit should be continuously developed.
Chip scale package (CSP) is a kind of high density package technical widely used at present. FIG. 1 is a schematic, cross sectional view of a chip package structure of a conventional optical integrated circuit. Referring to FIG. 1, a silicon structure 110 of the conventional chip package structure 100 includes a first surface 101 and a second surface 102 opposite to the first surface 101. The circuit layer 120 and an optical sensing chip 130 electrically connected to the circuit layer 120 are disposed on the first surface 101 of the silicon substrate 110, and covered by a transparent layer 140. The circuit layer 120 is electrically connected to outside component by leads 150 and solder balls 160. The second surface 102 of the silicon substrate 110 is usually enclosed by an encapsulation 170.
However, in the conventional chip package structure 100, the silicon substrate 110 is merely used for bearing the circuit layer 120 and the optical sensing chip 130, but could not be electrically connected to outside component such as printed circuit board. Thus, the silicon substrate 110 could not be electrically connected to ground.